1. Technical Field
The described embodiments pertain to interpreting location data and other data about a person collected from mobile devices and networked services.
2. Description of Related Art
Many mobile devices can record location and other information. Having a temporal record of where the user goes is useful for a variety of applications, including recommendation systems, life logging, and goal tracking. However, there are a number of obstacles to building useful applications on top of currently available data streams.
First, data streams are noisy, imprecise, and sometimes unavailable. Global Positioning System (GPS) technology, for example, can be confused by surrounding buildings or other features and is not available indoors. Cell tower triangulation is imprecise and is unavailable in areas without proximate cell towers. WiFi triangulation is error-prone and also unavailable in the absence of nearby WiFi networks.
Second, sensor readings (e.g., from satellite signals or other radio waves) consume significant power at the sensing device. Due to limited battery power in the sensing device, sensor readings are done sparingly. Fewer readings increase the uncertainty in data due to significant gaps between sensor readings.
Third, people generally think about their lives as a collection of time periods with some semantic meaning attached to each period, with a range of levels of abstraction. Raw location data in the form of latitude/longitude readings has no semantic content, and thus does not indicate how users perceive corresponding events.